178 REPOKT— 1895. 



often eclipse the effects of earthquakes, fslioukl, by pi'oper instalment of 

 the instruments, Ije as far as possible minimised. 



(e) Conclusions. 



If we except the curious results respecting the velocity of propagation 

 of motion which we might expect to find, and which apparently exists in 

 an epifocal area, the phenomenon of greatest interest, the study of which 

 may lead us to important conclusions respecting the physical constitution 

 of the interior of our globe, are the so-called preliminary tremors of earth- 

 quakes which are often continued as superimposed serrations on the quasi- 

 elastic motions. In Japan these have been recorded and studied for the 

 last 15 years, but it has only been within the last year or two that their 

 appearance has been recognised in Europe. 



All that I know about these latter records is what I learn by letters 

 from Dr. E. von Rebeur-Paschwitz, and what I have seen in the publica- 

 tions of Dr. Agamennone and other Italian observers, and the conclusion 

 is that these tremors are the reappearance of a phenomenon which has for 

 so many years puzzled seismologists in Japan. If this is so, and if they 

 really possess the abnormally high velocities attributed to them, seismo- 

 logists may be on the verge of probing our earth to depths greater than 

 it was thought probable that the study of earthquakes could possibly lead. 

 Although something farther may yet be learned by studying the elastic 

 gravitational surface disturbances, we know that whether they are recorded 

 on paths of about 600 miles in length in Japan, or on paths of 6,000 miles 

 in length between Japan and Europe, they travel at a rate of about 

 ?> km. per second. All that is now required is to increase the accuracy of 

 the observations by adopting such methods of noting the arrival of these 

 disturbances that the records at each station i-efer to the same phase of 

 motion. 



Before the short list below was completed, I unfortunately lost my 

 library and everything else by tire. It is therefore possible that some of 

 my quotations may be incomplete and perhaps inaccurate. Such writings 

 as have been referred to, so far as I am able to give them, are as 

 follows : — 



Heferences. 



Dr. A. Schmidt (Stutt- Wellenbcweguno: nnrl Erdhehen. ' .Talireshefte cles YereinH 

 gart). fiir vaterl. Naturkunde in Wiirtt.,' 1888. 



„ „ . . Untonsucliungeu iiber zwci neuero Erdbeben, das Schwei- 



zerische vom 7. Januar 1S89 iinddas Nord-Amerikanische 

 vom HI. August 188G. Ibid., 18'iO. 

 P. Tacchini . . . Terremoto calabro-messinese del IG Novembre 1894. 



' Reale Accademia dei Lincei,' vol. ,3, p. 27.5. 

 „ ... Sulla reyi.strazionc a Rmua del terremoto calabro-messinese 



del 16 Novembre 18!»4. Ibid., p. 3G5. 

 Dott. A. Cancani . . Sulla velocita di propagazione del terremoto di Constanti- 



nopoli del 10 Luglio 1894. Ibid., p. 409. 

 „ . . . Sugli strumenti pin adatti alio studio delle grandi ondula- 

 zione provenienti da centri sismici lontani. Ibid., 

 p. 551. 

 ,, . . . Sulle ondulazioni provenienti da centri sismici lontani. 

 ' Annali dell Officio Centrale di Meteorologiae Geodina- 

 mica,' vol. 15. part 1, 189.3. 

 Dott. G. Agamennone . Velocitil di propagazione delle principali scosse di terre- 

 moto di Zantc ncl recente periodo sismico del 1893. 

 ' Reale Accademia dei Lincei,' vol. 2, p. 392. 



